Any dark color glass back is going to show fingerprints. After all, they are all glass. However, orchid gray, because it is the lightest color of the 3 available, will show fingerprints the least.
I bought the orchid grey and love it. I have my phone in a Spigen NeoHybrid Crystal case, which is as close to going naked as you can get. It is a very thin, sleek clear case that really shows off the beauty of the phone. The minimalist, but protective bumper surrounding the case is a perfect matching orchid gray. You can hardly tell the phone is in a case.